Dowel



UNITED STATES PATENT OFFICE.

HARVEY S. MARSH, OF BASS RIVER, CANADA, ASSIGNOR OF ONE-HALF TO DAWVSON JOHNSON, OF BOSTON, MASSACHUSETTS.

DOWEL.

SPECIFICATION forming part of Letters Patent No. 475,407, dated May 24, 1892.

Application filed July 6, 1891. Serial No. 398,521. (No model.)

To all whom it may concern.-

Be it known that I, HARVEY S. MAnsH, of Bass River, in the county of Oolchester, Nova Scotia, Dominion of Canada, have invented certain new and useful Improvements in Dowels, of which the followingis a description sufficiently full, clear, and exact to enable any person skilled in the art or science to which said invention appertains to make and use the [0 same, reference being bad to the accompanying drawings, forming part of this specification, in which Figure 1 is an elevation of my improved dowel; Fig. 2,9. like view showing an alternative arrangementyFig. 3, a cross-section taken on line a: 03 in Fig. 2, showing the groove or thread; Fig. 4, a like view taken on line y y, showing the locking-teeth or serrations; and Fig. 5, an elevation showing modification in the formation of the thread; and Fig. 6, acrosssection taken on line z z in Fig. 5.

Like letters of reference indicate corresponding parts in the different figures of the drawings.

My invention relates especially toa double screw, which is adapted to be employed for doweling purposes, and alockin g device therefor; and it consists'in certain novel features hereinafter fully set forth and claimed, the objectbeing to produce a simpler, cheaper,

and more effective device of this character than is now in ordinary use.

The nature and operation of the improvement will be readily understood by all conver- 3 5 sant with such matters from the following explanation In the drawings, Arepresents the dowel considered as a whole, said dowel being constructed from a metallic rod, the center por- 40 tion (1 of which is toothed peripherally, forming a locking device. From said center portion the dowel is provided with a longitudi Dally-oblique groove in each direction, the portion f being grooved in diametrically-opposite direction from the correspondingportio'rig at the opposite side of theserrated portion; *The guide-points h on the screws thusformed are rounded and slightly reduced in diameter from the body of the dowel, the ends of the groovewalls 2' being beveled atj until flush with said guides.

In the use of my improvement the parts to be doweled together are bored or tapped in the ordinarymanner'when a'smooth" dowel-pin is used. "Tli'e guide p'ointsharethen insertedin the openings thusformed and said parts driven by clamps or other suitable mechanism onto the dowel. "The'groovfes of the parts gfrunning in opposite directions, the dowel A is caused to rotate, feedinggradually into the dowel-holes. The pitch of the teethdis in directionopposite that of the rotation of the dowel, so that when the parts being connected reach said serrated portion it will .turn freely therein until the parts are brought into contact. Said parts of bodies being moved to separate them would cause the dowel to tend to rotate in the opposite direction, in which event the teeth d would take in the materialof said bodies, locking the dowel against such rotation and preventing'accidental displacement thereof.

Instead of the guide-points h the dowelmay be furnished with gimlet-threaded points, the grooves of which gradually broaden to the grooves of the portions f g.

In Fig. 2 the serrated portion is shown disposed eccentrically, this form being employed when bodies which are of a different degree of hardness are being doweled together, the longer side g in this case being employed for the softer material and advancing more easily therein. The groove-walls of the portions f g may be notched or spurred atm on their edges, as shown in Fig. 5, said spurs inclining obliquely to the line of motion of the dowel, so that they do not interfere with the insertion of the dowels in the bodies, but look the same against being withdrawn. In this form the serrated portion (1 is not used, as said spurs serve the same purpose to prevent the withdrawal of the dowel.

One part, as g, may be omitted from the dowel and the remainder be employed as an ordinary lag-screw, the portion d forming the o 5 shank thereof and preventing its being turned out from the material.

Having'thns explained my invention,what I claim is 1. A metallic dpwel having a portion of its body toothed peripherally'fthe ends of said bodlatpppositesides of said tooth portion being respectively provided with longitudi nally-oblique grooves running in oppositedirections, substantially as and forthe purpose set forth.

2. A metallic dowel having a portion of its body toothed peripherally, the remainder of 4. The dowel A, provided with. the serrated portion (2 and grooved portions f 1, arranged [5 to operate substantially as described.

5. The dowel A, having the serrated portion d, grooved portionsf g, beveled at j, and the guide-points h, arranged to operate substantially as specified.

HARVEY S. MARSH.

Witnesses:

K. DURFEE, O. M. SHAW. 

